Foot drop, also commonly known as drop foot, is a common condition in which a person is unable to lift the front portion of one or both feet during walking or running due to a neurological or muscular condition which weakens the muscles of the foot. The condition causes the front portion of the person's foot to slap down on the floor or drag across the floor during walking or running. Persons suffering from foot drop often compensate by lifting the afflicted foot higher than normally necessary when moving to prevent the dropping foot from dragging or slapping on the floor. The irregular gait caused by the foot drop and the compensating movement by the person is known as a steppage gait.
Foot drop is typically treated by ankle-foot orthotics that either lock the person's ankle in place or support the front portion of the person's foot. However, the currently available ankle-foot orthotics often restrict the natural flexing motion of the ankle and foot during normal movement to prevent the foot drop motion, replacing the steppage gait with a different irregular gait. Ankle locking orthotics, such as the one described in U.S. Pat. No. 3,916,886, typically comprise rigid L-shaped members fitted against the back of the ankle and the underside of the foot to prevent the entire foot from flexing downwardly at the ankle U.S. Pat. No. 3,916,886 is hereby incorporated by reference in its entirety. However, because the L-shape member completely prevents downward flexing of the ankle at the foot, the foot cannot make the slight downward flexing movement that naturally occurs during walking or running. Ankle-foot orthotics that provide support to the front portion of the foot also impede the natural flexing of the foot and ankle during a natural gait. These orthotics typically comprise straps anchored to the person's calf or ankle at one end and anchored to the person's foot or shoe at the other end as disclosed in U.S. Pat. Nos. 4,817,589 and 7,458,950, to provide a tensile force preventing downward motion of the foot. U.S. Pat. Nos. 4,817,589 and 7,458,950 are also hereby incorporated by reference in their entirety. However, the straps used are often static or only have a limited elasticity to ensure sufficient tensile force is applied to support the front portion of the foot. The inelasticity of the straps also prevents the natural flexing of the foot and ankle during normal movement. The limited flexibility of presently available ankle foot orthotics effectively replace the irregular steppage gait with an irregular gait
In addition to being overly restrictive, currently available ankle-foot orthotics are often too bulky to fit easily into shoes. Similarly, currently available ankle-foot orthotics often require numerous straps or anchors to properly secure the orthotic to the person's ankle or foot increasing the difficulty of putting the orthotic on or taking it off. For example, the L-shaped members of ankle locking orthotics are often large and do not easily fit into shoes without extensive modification of the shoe. In addition, the rigidness of the L-shape member prevents wearers from pointing their toes to ease put on or takeoff the shoe. Similarly, strap orthotics often employ a plurality of straps and anchors that must be attached to the shoe or foot to properly attach the orthotic to the person's ankle and foot. The straps and the anchors may be difficult to remove from the shoe if the person wants to remove or change shoes. The complexity and the difficulty of putting on and taking off the currently available orthotics often cause wearers to spend considerable time putting on or taking off orthotic or forgoing the orthotic altogether.
An additional problem for strap orthotics is the positioning of the straps and where the straps are anchored on the wearer. Typically, the anchor locations for the straps are placed as high up on the calf as possible and as far down the foot or shoe as possible to achieve the maximum tensile force. However, the higher up the calf or further down the foot the anchor points are placed, the more visible and cumbersome the orthotic becomes for the user. Similarly, the greater the number of straps, the more support is provided for the foot. As with the positioning of the anchor locations, the greater the number of straps, the more visible and cumbersome the orthotic becomes for the wearer. Similarly, the positioning of the straps may be uncomfortable for users if the straps are pressed against the person's foot or ankle. The straps may rub against the person's legs or feet during movement causing chaffing or other discomfort.